Mar 03

Determine If Distribution Group is Being Used in 365 Exchange

“What distribution groups are in use?” and “How many emails are sent to a specific distribution group per month?” are common questions I receive with 365 Exchange or Exchange.  Unfortunately, there is nothing built in that tracks how many emails on sent to a distribution group.  However we can use Get-MessageTrace to count the number of messages sent to a distribution group for a time range with the max being 30 days.  Also note, the by default PageSize returns 1000 items but you can increase the PageSize to 5000 items.  For example, to get the number of emails sent to the distribution group everyone@domain.com for a single day we can use:

Using this method, we can count the number of emails sent to each distribution group each day and store the results in an output file.  We can then query those output files and create a report.  In my example, the report will show the total emails sent to each distribution group by month and go back 12 months.  Now without further ado, let’s get to the two scripts needed.

365_DGCounter.ps1

Note: [DateTime]::Today returns 12:00 AM of the Current Date.  Let’s assume the date is currently 3/3/2016.  The script above would return the range 3/2/2016 12:00 AM to 3/3/2016 12:00 AM.  Running this script will actually return the email counts from yesterday since today has not ended.

365_DGCounterReport.ps1